ifrpc
v2.0.0
Published
RPC interface for iframes (or popups)
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ifrpc
Iframe (or popup) RPC interface.
About
This library is designed for use in managing frame to frame control. Either
in the case of 3rd party parent frames managing an iframe(s). Or in the case
of a window managing popup windows it created with window.open()
.
You must have control over both frames involved (referred to as peers). This library needs to be included in both origins.
Installation
Run:
npm install ifrpc --save
Then include node_modules/ifrpc/src/ifrpc.js
in your web build process or as a
<script>
tag.
Repeat this process for both peers if they are separate web applications.
Setup
The ifrpc system must be initialized by both sides as they use the window.postMessage
interface for communicating. Care should be taken in setting the origin correctly
from both contexts.
Example from the parent frame who's html includes an iframe with src of
https://iframe
:
const iframe = document.querySelector('iframe').contentWindow;
const iframeRPC = ifrpc.init(iframe, {peerOrigin: 'https://iframe'});
And in the code for the aforementioned iframe:
const parentRPC = ifrpc.init(self.parent, {peerOrigin: 'https://parent'});
Usage
With setup completed you can now use ifrpc to add command handlers and trigger events. Commands are defined by either application and they are fulfilled by a JavaScript function. The return value (or exception) of these functions will be serialized (via structured clone algo) and sent to the peer frame. The invocation of commands is a Promise based interface so the caller doesn't need to be concerned with the mechanics of the message passing.
The main functions to use are:
ifrpc.init(frame, [{options}])
:frame
should be the frame/window object you wish to communicate with.options
is an optional object with config options:peerOrigin
: The expected origin of the peer for security.magic
: A special string value used to disambiguate postMesssage communication.
- Returns and
RPC
object.
<RPC>.addCommandHandler(name, callback)
:name
should any string.callback
should be afunction
orasync function
whose return value will be sent to the invoking peer.
<RPC>.addEventListener(name, callback)
:name
should any string.callback
should be afunction
orasync function
.
<RPC>.triggerEvent(name, ...args)
:name
is the event name defined by the peer frame with<RPC>.addEventListener
.
<RPC>.invokeCommand(name, ...args)
:name
is the command name defined by the peer frame with<RPC>.addCommandHandler
.- Returns a
Promise
that resolves with the eventual return value of the command handler's callback. If the command handler throws an exception thePromise
will reject with aniprc.RemoteError
exception describing the remote error.
Examples
Each of these examples shows code from 2 applications who are presumed to be peers. Peers meaning that one is an iframe of the other.
Simple ping/pong
rpcForIframe.addCommandHandler('ping', () => 'pong');
const pong = await rpcForParent.invokeCommand('ping');
console.assert(pong === 'pong');
Argument passing
rpcForIframe.addCommandHandler('sum', (a, b) => a + b);
const sum = await rpcForParent.invokeCommand('sum', 1, 1);
console.assert(sum === 2);
Async handler
rpcForIframe.addCommandHandler('soon', async () => {
await somethingAsync();
return true;
}
const soon = await rpcForParent.invokeCommand('soon');
console.assert(soon === true);
Simple event
rpcForIframe.addEventListener('hello', () => {
console.warn("The peer frame said hello");
});
rpcForParent.triggerEvent('hello');
Event with args
rpcForIframe.addEventListener('hello', whom => {
console.warn("The peer frame said hello to", whom);
});
rpcForParent.triggerEvent('hello', 'Bob');